Non-destructive inspection (NDI) of structures involves thoroughly examining a structure without harming the structure or requiring significant disassembly of the structure. Non-destructive inspection is typically preferred to avoid the schedule, labor, and costs associated with removal of a part for inspection, as well as avoidance of the potential for damaging the structure. Non-destructive inspection is advantageous for many applications in which a thorough inspection of the exterior and/or interior of a structure is required. For example, non-destructive inspection is commonly used in the power generation to inspect gas turbine engine structures for any type of internal or external damage to or defects (flaws) in the structure. Inspection may be performed during manufacturing or after the completed structure has been put into service, including field testing, to validate the continued integrity and fitness of the structure.
During NDI, one or more sensors may move over the portion of the structure to be examined, and receive data regarding the structure. Various types of sensors may be used to perform non-destructive inspection. One or more sensors may move over the portion of the structure to be examined, and receive data regarding the structure. For example, a pulse-echo (PE), through transmission (TT), or shear wave sensor may be used to obtain ultrasonic data, such as for thickness gauging, detection of laminar defects and porosity, and/or crack detection in the structure. Resonance, pulse-echo, or mechanical impedance sensors are typically used to provide indications of voids or porosity, such as in adhesive bondlines of the structure. High resolution inspection of gas turbine structures is commonly performed using ultrasonic testing (UT) to provide an image of the part or structure under inspection. Data acquired by sensors is typically processed and then presented to a user via a display as a graph of amplitude of the received signal. To increase the rate at which the inspection of a structure is conducted, a scanning system may include arrays of inspection sensors, i.e., arrays of transmitters and/or detectors.
Ultrasonic transducers may include delay lines. Delay lines for ultrasonic transducers are typically made of plexiglass or similar material which is hard and must be machined to shape. NDI personnel do not typically have this capability. Lead times from manufacturers producing delay lines is oftentimes two or more weeks which is insufficient to meet NDI demands.
Therefore, a method of making a flexible delay line for an ultrasonic transducer, a flexible delay for a transducer, and a transducer that do not suffer from the above drawbacks are desirable in the art.